There is widely known an Ultra Wide Band-Impulse Radio (UWB-IR) system as a background art of the present technical field. The UWB-IR system is a system for making communication by sending a waveform of a pulse width in a very short time, and a communication signal has a remarkably wide frequency bandwidth due to a short-time pulse width. Pulse polarity modulation, phase shift keying, on off keying, pulse amplitude modulation (PAM), pulse position modulation (PPM) and the like are known as modulation systems used for the UWB-IR communication system. The pulse polarity modulation and the phase shift keying among them are a system for sending information on a phase of a carrier wave, in which phase continuity and phase reproduction are required on the transmission side and the reception side, respectively, which causes a complicated configuration of the transceiving device. The communication system for communicating information on a phase of a carrier wave is called coherent communication method. On the other hand, the pulse amplitude modulation PAN, the on off keying (OOK) and the pulse position modulation PPM do not require phase information for demodulation, and thus a configuration of the transceiving device is simple. In particular, the on off keying (OOK) and the pulse position modulation PPM perform demodulation by determining the presence and positions of pulses, and thus a device configuration is so simple and can be realized at low cost.
For example, PTL 1 discloses therein a UWB-IR communication method for transmitting information by changing positions in time domain (timing) for sending pulses depending on transmission data (FIG. 5 in PTL 1). There is illustrated an example in which a signal for which a pulse position is delayed by d is used when transmission data is 0′ unlike when transmission data is 1′. Further, NPL 1 similarly discloses therein a UWB-IR communication method for transmitting information by changing positions in time domain (timing) of transmission pulses according to transmission data (Equation (1) in NPL 1).
According to Equation (1) in NPL, there is described a method in which a position in time domain (timing) at the j-th pulse is changed by dj(k)(u) according to transmission data thereby to generate a transmission signal.